In recent years, rotating electrical machines used as electric motors and electric generators are required to have a small size, high output, and a high quality. For example, in the case of a rotating electrical machine mounted on a vehicle, a space for mounting the rotating electrical machine is being reduced while output improvement is required. As a conventional rotating electrical machine, a structure is known in which divided cores are inserted from an outer circumference side into a stator coil used for a stator (for example, see Patent Document 1). Since divided cores obtained by dividing a core for every three teeth are used, the number of components is reduced as compared to the case of dividing a core for every tooth or every two teeth, thereby providing an effect of improving productivity.
Another structure is shown in which a back yoke is provided around a ring body formed by a plurality of teeth joined via deformable thin portions (for example, see Patent Document 2). In a rotating electrical machine disclosed in Patent Document 2, the deformable thin portions are deformed to insert a coil into a slot, thus providing an effect of improving a coil insertion property and reducing the number of components.